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Compaq 486 Maintenance And Service Manual

Compaq 486 Maintenance And Service Manual

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Notice
The information in this guide is subject to change without notice.
Compaq Computer Corporation shall not be liable for technical or editorial
errors or omissions contained herein; nor for incidental or consequential
damages resulting from the furnishing, performance, or use of this material.
This guide contains information protected by copyright. No part of this guide
may be photocopied or reproduced in any form without prior written consent
from Compaq Computer Corporation.
Copyright 1991 Compaq Computer Corporation.
All rights reserved.
Printed in the USA
COMPAQ, DESKPRO, SYSTEMPRO, LTE, FASTART
Registered United States Patent and Trademark Office.
SLT is a trademark of Compaq Computer Corporation.
The software described in this guide is furnished under a license agreement
or nondisclosure agreement.
The software may be used or copied only in
accordance with the terms of the agreement.
Product names mentioned herein may be trademarks and/or registered trademarks
of their respective companies.
MAINTENANCE AND SERVICE GUIDE
COMPAQ PORTABLE 486c Personal Computer
First Edition (October 1991)
Text Number 128987-001

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  • Page 1 Notice The information in this guide is subject to change without notice. Compaq Computer Corporation shall not be liable for technical or editorial errors or omissions contained herein; nor for incidental or consequential damages resulting from the furnishing, performance, or use of this material. This guide contains information protected by copyright.
  • Page 2 Chapter 1. Specifications Introduction This chapter provides physical, environmental, and performance specifications for the following COMPAQ PORTABLE 486c Personal Computer subsystems: o System Unit o Full Function 101/102 Key Keyboard o Active Matrix Color VGA Display o Power Supply o 3 1/2 inch 1.44 Megabyte Diskette Drive o 210 and 120 Megabyte Fixed Disk Drives Chapter 1.1 System Unit =============================================================================...
  • Page 3 Temperature Operating Nonoperating Relative Humidity (noncondensing) Operating Nonoperating Maximum Unpressurized Altitude Operating Nonoperating ----------------------------------------------------------------------------- Cooling ----------------------------------------------------------------------------- Shock ----------------------------------------------------------------------------- Vibration Operating Nonoperating ============================================================================= Chapter 1.2 Keyboard ============================================================================= ----------------------------------------------------------------------------- Dimensions Height Depth Width ----------------------------------------------------------------------------- Weight ----------------------------------------------------------------------------- Number of Keys ----------------------------------------------------------------------------- Cable Compressed Extended ----------------------------------------------------------------------------- Interface...
  • Page 4 Width ----------------------------------------------------------------------------- Diagonal Size ----------------------------------------------------------------------------- Mounting ----------------------------------------------------------------------------- Tilt Angle ----------------------------------------------------------------------------- Display ----------------------------------------------------------------------------- Color Capability ----------------------------------------------------------------------------- Brightness ----------------------------------------------------------------------------- Maximum Pixel Resolution (Text and Graphics) ----------------------------------------------------------------------------- Operating Frequency ----------------------------------------------------------------------------- VDC Input Nominal Voltage Current Maximum Power Maximum ============================================================================== Chapter 1.4 Power Supply ============================================================================= ----------------------------------------------------------------------------- Input Requirements...
  • Page 5 NOTE: These values are maximum values based on nominal operating conditions for temperature, line voltage, frequency, and altitude. ----------------------------------------------------------------------------- * 60W maximum available through EISA expansion slots. ============================================================================= Chapter 1.5 Diskette Drive ============================================================================= ----------------------------------------------------------------------------- Diskette Size Capacity Per Diskette (high/low) LED Indicators Read/Write (high density) Read/Write (low density)
  • Page 6 Drives Supported Form Factor Drive Height Drive Weight Drive Type (logical) Drive Speed Transfer Rate (per second) Head Buffer (max) Sector Interleave Seek Times Track to Track Average Maximum Cylinders Physical Logical Read/Write Heads Physical Logical Sectors Per Track Physical Logical Bytes Per Sector =============================================================================...
  • Page 7 Chapter 2. Power On Self Test (POST) Introduction This chapter lists the subassemblies checked by the Power On Self Test (POST) and briefly describes the types of error codes that can occur. also includes problem isolation procedures and a flowchart for quick reference.
  • Page 8 Access the fixed disk drive. You will know that the fixed disk drive password is set when the DriveLock icon (see illustration of DriveLock icon below) appears on the screen. If this occurs, you must enter the fixed disk drive password to continue.

  • Page 9: Chapter 2.4 Problem Isolation Flowchart

    Disconnect the AC power. Disassemble the computer to reach the I/O board (refer to Chapter 5). Locate the power on password switch (SW5) on the I/O board; set the switch to ON (Figure 2-1). Reconnect AC power. Turn on the computer and allow it to complete POST. Turn the computer off.
  • Page 10 troubleshooting information.

  • Page 17: Chapter 3. Error Messages And Codes

    Chapter 3. Error Messages and Codes This chapter contains Power On Self Test (POST) messages, Diagnostic error codes, and memory error codes for the COMPAQ PORTABLE 486c Personal Computer. The messages and codes appear in tables that list the message or error code, a description of the error or its probable cause, and the action recommended to resolve the error condition.
  • Page 18 Mismatch 174 - EISA 1 Short Configuration/ Slot Mismatch 175 - EISA 1 Short Configuration/ Slot Mismatch 176 - Slot with 1 Short Unreadable ID 177 - Configuration 1 Short Not Complete ----------------------------------------------------------------------------- Message Beeps ----------------------------------------------------------------------------- 178 - Processor 1 Short Configuration ----------------------------------------------------------------------------- XX000Y ZZ *...
  • Page 19 ----------------------------------------------------------------------------- 605 - Diskette Drive 2 Short Type Error ----------------------------------------------------------------------------- 610 - External None Storage Module Failure. F1 when ready. ----------------------------------------------------------------------------- 701 - Coprocessor None Error ----------------------------------------------------------------------------- 1151 - Comm Port 1 2 Short Configuration Error 1152 - Comm Port 2 2 Short Configuration Error...

  • Page 20: Chapter 3.2 Diagnostic Error Codes

    ----------------------------------------------------------------------------- 1782 - Disk None Controller Failure ----------------------------------------------------------------------------- Message Beeps ----------------------------------------------------------------------------- 1790 - Disk 0 Error None ----------------------------------------------------------------------------- 1791 - Disk 1 Error None ----------------------------------------------------------------------------- XX000Y ZZ Parity None Check 2 ----------------------------------------------------------------------------- Audible 1 Short ----------------------------------------------------------------------------- Audible 2 Short ----------------------------------------------------------------------------- (RESUME = None "F1"...
  • Page 21 Diagnostic error codes occur if the system recognizes a problem while running the Diagnostics program (refer to the SUPPORT SOFTWARE MAINTENANCE AND SERVICE GUIDE for additional information on running the Diagnostics software). These error codes help identify possible defective subassemblies. Tables 3-2 through 3-12 list possible error codes, a description of the error condition, and the action required to resolve the error condition.
  • Page 22 unexpected 101 - 95 Coprocessor and processor board conflict 101 - 96 Refer to Authorized Compaq Dealer Service Bulletin No. 84. ----------------------------------------------------------------------------- Error Code Description ----------------------------------------------------------------------------- 102 - 01 Coprocessor initial status word incorrect 102 - 02 Coprocessor initial control word incorrect 102 - 03 Coprocessor...
  • Page 23 103 - 03 DMA word controller test failed 104 - 01 Interrupt controller master test failed 104 - 02 Interrupt controller slave test failed 104 - 03 Interrupt controller software RTC is inoperative 105 - 01 Port 61 bit 6 not at zero 105 - 02 Port 61 bit 5 not at zero 105 - 03...
  • Page 24 109 - 02 CMOS clock rollover test failed 109 - 03 CMOS clock test, CMOS not properly initialized ----------------------------------------------------------------------------- Error Code Description ----------------------------------------------------------------------------- 110 - 01 Programmable timer load data test failed 110 - 02 Programmable timer dynamic test failed 110 - 03 Programmable Timer No.
  • Page 25 113 - 50 BIOS dispatch of processor 113 - 51 Processor is unavailable or nonexistent 113 - 52 Time out waiting for completion of test 113 - 54 Time out waiting for serial semaphore 113 - 56 Unexpected interrupt occurred during test 114 - 01 Speaker test failed =============================================================================...
  • Page 26 204 - 02 Error during saving program memory in address test ----------------------------------------------------------------------------- Error Code Description ----------------------------------------------------------------------------- 204 - 03 Error during restore of program memory in address test 204 - 04 A20 address test failed 204 - 05 Page hit address test failed 205 - 01 Walking 1/0 test failed...
  • Page 27 page not present 211 - xx Random Pattern Test 211 - 01 Memory random pattern test failed 211 - 02 Error during saving program memory and random pattern in write/read test 211 - 03 Error during restore of program memory and random pattern in write/read test 211 - 04 Insufficient memory to...
  • Page 28 ----------------------------------------------------------------------------- Error Code Description ----------------------------------------------------------------------------- 303 - 08 Keyboard LED test, command byte restore test failed 303 - 09 Keyboard LED test, LEDs failed to light 304 - 01 Keyboard typematic test failed 304 - 02 Unable to enter mode 3 304 - 03 Incorrect scan code from keyboard...
  • Page 29 402 - 09 Printer interrupt and data register failed 402 - 10 Printer interrupt and control register failed ----------------------------------------------------------------------------- Error Code Description ----------------------------------------------------------------------------- 402 - 11 Printer interrupt, data, and control register failed 402 - 12 Printer interrupt and loopback failed 402 - 13 Printer interrupt, loopback, and data register failed...
  • Page 30 507 - 01 Video 40 x 25 Mode Test Failed 508 - 01 Video 320 x 200 Mode Color Set 0 Test Failed 509 - 01 Video 320 x 200 Mode Color Set 1 Test Failed 510 - 01 Video 640 x 200 Mode Test Failed 511 - 01 Video Screen Memory...
  • Page 31 610 - 02 Exceeded maximum hard error limit 610 - 03 Previously exceeded maximum soft error limit ----------------------------------------------------------------------------- Error Code Description ----------------------------------------------------------------------------- 610 - 04 Previously exceeded maximum hard error limit 610 - 05 Failed to reset controller 610 - 06 Fatal error while reading 610 - 07 Fatal error while writing...
  • Page 32 ----------------------------------------------------------------------------- 699 - 00 Diskette drive/media ID error, rerun COMPAQ EISA Configuration utility ============================================================================= Table 3-8. Serial Test Error Codes ============================================================================= Error Code Description ----------------------------------------------------------------------------- 1101 - 01 Serial Port Test: UART DLAB bit failure 1101 - 02 Serial Port Test; line input or UART fault 1101 - 03 Serial Port Test;...
  • Page 33 1101 - 14 Serial Port Test; DRIVER/RECEIVER data failure 1101 - 15 Serial port test modem detection 1101 - 16 Serial port test, modem ROM checksum 1101 - 17 Serial port test, tone detection 1101 - 18 Serial port test, COM3 set to invalid interrupt 1101 - 19 Serial port test, COM4...
  • Page 34 1201 - 08 UART TX/RX buffer failure 1201 - 09 INTERRUPT circuit failure 1201 - 10 COM1 set to invalid interrupt 1201 - 11 COM2 set to invalid interrupt 1201 - 12 DRIVER/RECEIVER control signal failure ----------------------------------------------------------------------------- Error Code Description ----------------------------------------------------------------------------- 1201 - 13 UART control signal...
  • Page 35 1202 - 21 Modem timed out waiting for SYNC (analog loopback answer mode) 1202 - 22 Modem timed out waiting for modem response (analog loopback answer mode) 1202 - 23 Modem exceeded data block retry limit (analog loopback answer mode) 1203 - xx Modem External Termination Test...
  • Page 36 1210 - 08 Modem timed out waiting for remote response 1210 - 09 Modem exceeded maximum redial limit 1210 - 10 Line quality prevented remote connection 1210 - 11 Modem timed out waiting for remote connection 1210 - 17 Tone detection failure ============================================================================= Table 3-10.
  • Page 37 select test failed 1716 - xx Fixed disk drive conditional format test failed 1717 - xx Fixed disk drive Error Correction Code test failed 1719 - xx Fixed disk drive power mode test 1719 - 01 Exceeded maximum soft error limit 1719 - 02 Exceeded maximum hard error limit...
  • Page 38 1719 - 47 Failed to park heads 1719 - 48 Failed to move disk table to RAM ----------------------------------------------------------------------------- Error Code Description ----------------------------------------------------------------------------- 1719 - 49 Failed to read media in file write test 1719 - 50 Failed file I/O write test 1719 - 51 Failed file I/O read test 1719 - 52...
  • Page 39 1719 - 68 Failed to read long 1719 - 69 Failed to read drive size from controller 1719 - 70 Failed translate mode 1719 - 71 Failed nontranslated mode 1719 - 72 Bad track limit exceeded 1719 - 73 Previously exceeded bad track limit 1719 - 74 Failed sleep mode...
  • Page 40 1906 - 08 Unable to servo write ----------------------------------------------------------------------------- Error Code Description ----------------------------------------------------------------------------- 1906 - 09 Unable to format 1906 - 10 Format mode error 1906 - 11 Drive recalibration error 1906 - 12 Tape not servo written 1906 - 13 Tape not formatted 1906 - 14 Drive timeout error...
  • Page 41 1906 - 34 No data detected 1906 - 35 Power on reset occurred 1906 - 91 Power lost during test ============================================================================= Table 3-12. Video Test Error Codes ============================================================================= Error Code Description ----------------------------------------------------------------------------- 2402 - 01 Video memory test failed 2403 - 01 Video attribute test failed 2404 - 01 Video character set test...

  • Page 42: Chapter 3.3 Memory Error Codes

    2420 - 01 Video attribute test failed 2421 - 01 Video 640 x 200 graphics mode test failed 2422 - 01 Video 640 x 350 16 color set test failed 2423 - 01 Video 640 x 350 64 color set test failed 2424 - 01 Video monochrome text mode test failed...
  • Page 43 ------------------------ Failed byte. -------------------------- Always 000. ----------------------------- Failed address. 08, 10, 20, 40, 80, ?? 00 = parity bit 01 = data bit 0 02 = data bit 1 04 = data bit 2 08 = data bit 3 10 = data bit 4 20 = data bit 5 40 = data bit 6 80 = data bit 7...

  • Page 44: Chapter 4. Illustrated Parts Catalog

    Chapter 4. Illustrated Parts Catalog This chapter provides an illustrated parts breakdown and identifies the spare parts for the standard features of the COMPAQ PORTABLE 486c Personal Computer. Chapter 4.1 Illustrated Parts Breakdown System Unit...
  • Page 45 Table 4-1. System Unit ============================================================================= Description ----------------------------------------------------------------------------- System Chassis Front Bezel Rear Panel Handle Connector Cover Enhanced Option Cover Base Panel Tilt Base Power Supply Fan Assembly Keylock AC Power Cord (U.S./Canada) (UK) ----------------------------------------------------------------------------- * Not shown ============================================================================= Active Matrix Color Display Table 4-2.
  • Page 46 ============================================================================= Description ----------------------------------------------------------------------------- Front Bezel Display Assembly Display Shield Backlight Assembly Display Shield Video Cable Display Inverter Board ============================================================================= Mass Storage Devices Table 4-3. Mass Storage Devices ============================================================================= Description ----------------------------------------------------------------------------- 210 Megabyte Fixed Disk Drive 120 Megabyte Fixed Disk Drive 3 1/2 inch 1.44 Megabyte Diskette Drive =============================================================================...
  • Page 47 Table 4-4. Cables ============================================================================= Description ----------------------------------------------------------------------------- Power Distribution Board Video Cable ============================================================================= Processor Board Spare Part Number 128935-001 128903-001...
  • Page 48 Table 4-5. COMPAQ PORTABLE 486c Personal Computer Processor Board Connectors ============================================================================= Memory Module Connectors, Slots 2, 3, and 4 Intel 486 33 MHz Microprocessor Connector System ROM Connector Real Time Clock/Battery Connector Memory Module Connector, Slot 1 ============================================================================= I/O Board Table 4-6.
  • Page 49 Table 4-7. Processor and Standard Board Assemblies and Subassemblies ============================================================================= Item Description ----------------------------------------------------------------------------- Processor Board 4 Megabyte Memory Module System ROM Real Time Clock/Battery I/O Board Video Board Display Inverter Board Speaker Assembly ============================================================================= Keyboard Spare Part Number 128897-001 118741-001 128939-001 126570-001 128949-001...

  • Page 50: Chapter 4.2 Spare Part Numbers

    Table 4-8. Keyboards ============================================================================= Description ----------------------------------------------------------------------------- U.S. English Keyboard template UK English German French Italian Spanish Danish Norwegian Swedish/Finnish Swiss Portuguese Latin American Belgian ----------------------------------------------------------------------------- * Not shown ============================================================================= Chapter 4.2 Spare Part Numbers The following table provides a list of all of the spare part descriptions and part numbers for standard features of the COMPAQ PORTABLE 486c Personal Computer.
  • Page 51 ----------------------------------------------------------------------------- System Unit: System Chassis Front Bezel Rear Panel Handle Connector Cover Enhanced Option Cover Base Panel Tilt Base Power Supply Fan Assembly Keylock AC Power Cord (U.S./Canada) AC Power Cord (UK) Active Matrix Color Display: Front Bezel Display Assembly Display Shield Backlight Assembly Display Shield...
  • Page 52 Belgian Documentation: Service Aids Kit Maintenance and Service Guides: COMPAQ PORTABLE 486c Personal Computer Options and Peripherals Volume 1 Options and Peripherals Volume 2 Options and Peripherals Volume 3 Support Software Operations Guide COMPAQ PORTABLE 486c PERSONAL COMPUTER TECHNICAL REFERENCE GUIDE COMPAQ SERVICE QUICK REFERENCE GUIDE Diagnostics...
  • Page 53 Screw Kit 6-32, MA, TH, T-15, CS Screw Kit 6-32 x 1/4, Torx, TT, HI, T/WSr Screw Kit 6-32 x 1/4, S-Torx, PNHD Screw Kit 6-32 x 1/4, TAPTITE, HT Screw Kit 6-32 x 1/2, S-Torx, TT ============================================================================= 136967-001 119548-001 136966-001 128212-001 136974-001...

  • Page 54: Chapter 5. Removal And Replacement Procedures

    Chapter 5. Removal and Replacement Procedures Introduction This chapter provides module level removal and replacement procedures for the COMPAQ PORTABLE 486c Personal Computer. After completing all removal and replacement procedures, run the Diagnostics program to verify that all components operate properly. SOFTWARE MAINTENANCE AND SERVICE GUIDE for information on installing new or updated utilities when adding or removing options.
  • Page 55 grounding are necessary precautions to prevent damage. precautions to protect equipment from static damage: o To avoid hand contact, transport products in static safe containers such as tubes, bags, or boxes. o Protect all electrostatic parts and assemblies by conductive or approved containers or packaging.
  • Page 56 Grounding Workstations To provide a grounded workstation, do the following: o Cover workstations with approved static dissipating material. wrist strap connected to work surface and properly grounded tools and equipment. o Use static dissipating mats, heel straps, or air ionizers to give added protection.

  • Page 57: Chapter 5.3 Disassembly/Assembly Sequence Chart

    o Conductive foam o Conductive table top workstations with ground cord of 1 megohm resistance o Static dissipating table or floor mats with hard tie to ground o Field service kits o Static awareness labels o Wrist straps and footwear straps providing 1 megohm ñ 10% resistance o Material handling packages - Conductive plastic bags - Conductive plastic tubes...

  • Page 58: Chapter 5.4 Preparation Procedures

    |-- Real Time Clock/Battery |-- POWER SUPPLY 5.10 |-- FAN ASSEMBLY 5.11 |-- I/O BOARD 5.12 |-- BASE PANEL 5.13 |-- MASS STORAGE DEVICES |-- Diskette Drive |-- Fixed Disk Drive 5.14 |-- ACTIVE MATRIX COLOR DISPLAY |-- Front Bezel |-- Display Assembly |-- Backlight Assembly |-- Display Inverter Board...

  • Page 59: Chapter 5.5 Keyboard

    Disconnect all external devices (printer, monitor, and other devices) from the computer. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< Static electricity can damage the CMOS components. properly grounded before performing any of the following procedures. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< Screws in this system are not interchangeable. them with the component you removed. screws in the wrong place.
  • Page 60 Using a nonconductive probe, remove the access cover (Figure 5-3). Disconnect the keyboard cable by gently pulling the keyboard connector tab (Figure 5-4).

  • Page 61: Chapter 5.6 Rear Panel

    Carefully remove the keyboard cable from the cable slot (Figure 5-4). To replace the keyboard, reverse the steps in the above illustrations. Chapter 5.6 Rear Panel To remove the rear panel, complete the following steps: Push the tilt adjustment buttons on the sides of the computer in and tilt the display assembly forward (Figure 5-5).
  • Page 62 Lift the handle and remove two screws, using a Torx T-15 screwdriver (Figure 5-5). Pull the rear panel out and up, until the bottom latches are released from the slots (Figure 5-6). To replace the rear panel, complete the following steps: Position the rear panel on the computer by aligning the bottom latches...
  • Page 63 with the appropriate slots. Slide the rear panel down and forward, and secure with the two screws using a Torx T-15 screwdriver. Chapter 5.7 Options Cover To remove the options cover, complete the following steps: Remove the rear panel (Section 5.6). Using a Torx T-15 screwdriver, remove three screws from the top of the options cover (Figure 5-7).
  • Page 64 To replace the options cover, reverse the steps in the above illustration. Chapter 5.8 Standard Boards Video Board To remove the video board, complete the following steps: Remove the rear panel (Section 5.6). Remove the options cover (Section 5.7). Remove any expansion boards from the expansion slots (Refer to the COMPAQ PORTABLE 486c Personal Computer Reference Guide).
  • Page 65 (Figure 5-9). Carefully disconnect the video cable from the video board (Figure 5-9). Using a Torx T-10 screwdriver, remove the screw securing the video board (Figure 5-9). Carefully pull the video board out of the slot (Figure 5-9). To replace the video board, reverse the steps in the above illustration. Processor Board To remove the processor board, complete the following steps: Remove the rear panel (Section 5.6).
  • Page 66 Carefully pull the processor board out of the slot (Figure 5-10). To replace the processor board, reverse the steps in the above illustration. System ROM To remove the system ROM from the processor board, complete the following steps: Remove the rear panel (Section 5.6). Remove the options cover (Section 5.7).
  • Page 67 Using the ROM removal tool, grasp the ROM and gently pull up until it is released from the socket (Figure 5-11). To replace the system ROM, reverse the steps in the above illustration. NOTE: When replacing the system ROM, align Pin 1 with the dot on the system ROM socket.

  • Page 68: Chapter 5.9 Power Supply

    >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< The real time clock/battery contains a lithium battery that may explode if mishandled. Do not abuse, recharge, disassemble, or dispose of in fire. Use only replacement real time clock/battery modules supplied by Compaq Computer Corporation (part no. 126570-001). Disposal of the real time clock/battery should be accomplished within compliance of local regulations or returned to Compaq Computer Corporation by established parts return methods.

  • Page 69: Chapter 5.10 Fan Assembly

    Using a Torx T-15 screwdriver, remove three screws securing the power supply to the I/O board (Figure 5-13). Pull out the power supply with the switch bezel attached (Figure 5-13). Remove the switch bezel from the power supply (Figure 5-13). To replace the power supply, reverse the steps in the above illustration.

  • Page 70: Chapter 5.11 I/O Board

    Using a Torx T-10 screwdriver, remove the screw securing the fan assembly (Figure 5-14). Slide the fan assembly out (Figure 5-14). To replace the fan assembly, reverse the steps in the above illustration. Chapter 5.11 I/O Board To remove the I/O board, complete the following steps: Remove the rear panel (Section 5.6).

  • Page 71: Chapter 5.12 Base Panel

    Disconnect the fan assembly cable (Figure 5-15). Using a Torx T-10 screwdriver, remove the screw securing the internal keyboard connector to the display pan (Figure 5-15). Using a Torx T-15 screwdriver, remove seven screws securing the I/O board (Figure 5-15). To replace the I/O board, reverse the steps in the above illustration.

  • Page 72: Chapter 5.13 Mass Storage Devices

    Position the computer on the rear panel (Figure 5-16). Using a Torx T-15 screwdriver, remove the screw from the base panel (Figure 5-16). Remove the base panel by sliding it out toward the diskette drive side of the computer (Figure 5-16). To replace the base panel, reverse the steps in the above illustration.
  • Page 73 Using a Torx T-15 screwdriver, remove the screws securing the diskette drive cage; then swing the drive cage out (Figure 5-17). Using a Torx T-15 screwdriver, remove four screws securing the diskette drive to the drive cage (Figure 5-17). To replace the diskette drive, reverse the steps in the above illustration. Fixed Disk Drive To remove the fixed disk drive, complete the following steps: Remove the base panel (Section 5.12).
  • Page 74 Using a Torx T-15 screwdriver, remove the screws securing the fixed disk drive cage; then swing the drive cage out (Figure 5-18). Lift the fixed disk drive out of the cage and remove the shock mounts (Figure 5-19). To replace the fixed disk drive, reverse the steps in the above illustrations.
  • Page 75 Chapter 5.14 Active Matrix Color Display Front Bezel To remove the front bezel, complete the following steps: Remove the keyboard (Section 5.5). Pull the brightness and volume controls off (Figure 5-20). Remove four plastic screw covers from the front bezel (Figure 5-20). >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<...
  • Page 76 Display Assembly To remove the display assembly, complete the following steps: Remove the keyboard (Section 5.5). Remove the front bezel (Section 5.14). >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< The display inverter board contains High Voltage. surfaces of the display inverter board when removing the display assembly. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<...
  • Page 77 >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< When removing or inserting cables with ZIF connectors, do not pull, twist, or apply tension to cables. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< NOTE: The ZIF connectors in this product have mechanical latches that either slide forward and lift up or slide up to open. ZIF connectors are opened before attempting to remove the cable.
  • Page 78 Place the display assembly screen down on a soft, clean surface. Using a Phillips screwdriver, remove the four screws securing the display assembly to the backlight assembly (Figure 5-22). Carefully release the display assembly cables from the four corner brackets (Figure 5-22). Release the five tabs securing the backlight assembly to the display assembly (Figure 5-22).
  • Page 79 Remove the keyboard (Section 5.5). Remove the front bezel (Section 5.14). Remove the display assembly (Section 5.14). >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< The display inverter board contains high voltage. surfaces of the board. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< When removing or inserting cables with ZIF connectors, do not pull, twist, or apply tension to cables.
  • Page 80 Pull the display inverter board insulator aside to gain access to the screws (Figure 5-23). Using a Torx T-15 screwdriver, remove five screws securing the display inverter board (Figure 5-23). To replace the display inverter board, reverse the steps in the above illustration.

  • Page 81: Chapter 5.15 Power Distribution Board

    Carefully release the speaker assembly tabs and remove the speaker assembly from the display inverter board (Figure 5-24). To replace the speaker assembly, reverse the steps in the above illustration. Chapter 5.15 Power Distribution Board To remove the power distribution board, complete the following steps: Remove the keyboard (Section 5.5).
  • Page 82 on the display inverter board (Figure 5-25). Turn the computer around and remove the rear panel (Section 5.6). Remove the options cover (Section 5.7). Remove the video board (Section 5.8). Remove the processor board (Section 5.8). Remove the power supply (Section 5.9). Remove the fan assembly (Section 5.10).
  • Page 83 Using a Torx T-15 screwdriver, remove four screws securing the power distribution board (Figure 5-27). Carefully pull the I/O cables, diskette drive cable, fixed disk drive cable, and power cable through their respective slots and remove the power distribution board (Figure 5-27). To replace the power distribution board, reverse the steps in the above illustrations.

  • Page 84: Chapter 5.16 Keylock

    Chapter 5.16 Keylock To remove the keylock, complete the following steps: Remove the rear panel (Section 5.6). Remove the options cover (Section 5.7). Using a flathead screwdriver, remove the metal clip securing the keylock (Figure 5-28). Pull the keylock out of the computer (Figure 5-28).

  • Page 85: Chapter 5.17 Memory Expansion

    To replace the keylock, reverse the steps in the above illustration. Chapter 5.17 Memory Expansion Some of the memory expansion alternatives for the COMPAQ PORTABLE 486c Personal Computer are shown in Table 5-3. combinations of 2, 4, and 8 megabytes for a total of 32 megabytes. NOTE: Memory modules can be installed in any combination and in any available slot.
  • Page 86 4 MB 2 MB 4 MB 4 MB 4 MB 8 MB 8 MB 8 MB ============================================================================= 8 MB 8 MB 8 MB 8 MB 8 MB 8 MB 8 MB 8 MB 22 MB 24 MB 28 MB 32 MB...

  • Page 87: Chapter 6. Jumper And Switch Information

    Chapter 6. Jumper and Switch Information This chapter provides the switch settings for the COMPAQ PORTABLE 486c Personal Computer I/O board. default settings shown in the following table are set for the computer as configured by Compaq Computer Corporation. only when the system configuration changes. Table 6-1 lists the switch settings and describes the function of each switch.
  • Page 88 ----------------------------------------------------------------------------- ============================================================================= Enabled Controls the power on Disabled password. OFF is the default position and enables the power on password feature. ON will clear the power on password. Enabled Allows the configuration Disabled memory to be cleared. OFF is the default position and allows configuration memory to remain unchanged.

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